.TH std::experimental::ranges::adjacent_find 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::experimental::ranges::adjacent_find \- std::experimental::ranges::adjacent_find

.SH Synopsis
   Defined in header <experimental/ranges/algorithm>
   template< ForwardIterator I, Sentinel<I> S, class Proj =
   ranges::identity,

             IndirectRelation<projected<I, Proj>> Pred =                \fB(1)\fP (ranges TS)
   ranges::equal_to<> >

   I adjacent_find( I first, S last, Pred pred = Pred{}, Proj proj =
   Proj{} );
   template< ForwardRange R, class Proj = ranges::identity,

             IndirectRelation<projected<ranges::iterator_t<R>, Proj>>
   Pred = ranges::equal_to<> >                                          \fB(2)\fP (ranges TS)

   ranges::safe_iterator_t<R> adjacent_find( R&& r, Pred pred = Pred{},
   Proj proj = Proj{} );

   1) Searches the range [first, last) for two consecutive identical elements. Elements
   are compared using pred after being projected with proj.
   2) Same as \fB(1)\fP, but uses r as the source range, as if using ranges::begin(r) as
   first and ranges::end(r) as last.

   Notwithstanding the declarations depicted above, the actual number and order of
   template parameters for algorithm declarations is unspecified. Thus, if explicit
   template arguments are used when calling an algorithm, the program is probably
   non-portable.

.SH Parameters

   first, last - the range of elements to examine
   r           - the range of elements to examine
   pred        - predicate to use to compare the projected elements
   proj        - projection to apply to the elements

.SH Return value

   An iterator to the first of the first pair of identical elements, that is, the first
   iterator i such that both i and i + 1 are in the range [first, last) and
   ranges::invoke(pred, ranges::invoke(proj, *i), ranges::invoke(proj, *(i + 1))) !=
   false.

   If no such elements are found, an iterator that compares equal to last is returned.

.SH Complexity

   If the range is nonempty, exactly min((result - first) + 1, (last - first) - 1)
   applications of the predicate where result is the return value, and at most twice as
   many applications of the projection.

.SH Possible implementation

   template<ForwardIterator I, Sentinel<I> S, class Proj = ranges::identity,
            IndirectRelation<projected<I, Proj>> Pred = ranges::equal_to<>>
   I adjacent_find(I first, S last, Pred pred = Pred{}, Proj proj = Proj{})
   {
       if (first == last)
           return first;
       I next = first;
       ++next;
       while (next != last)
       {
           if (ranges::invoke(pred, ranges::invoke(proj, *first),
                                    ranges::invoke(proj, *next)))
               return first;
           ++next;
           ++first;
       }
       return next;
   }

.SH Example

    This section is incomplete
    Reason: no example

.SH See also

                 finds the first two adjacent items that are equal (or satisfy a given
   adjacent_find predicate)
                 \fI(function template)\fP
   unique        removes consecutive duplicate elements in a range
                 \fI(function template)\fP

.SH Category:
     * Todo no example
